1. Technical Field
The present invention relates to a relay. Specifically, the present invention relates to a relay having a function of emitting light to indicate an operation.
2. Related Art
Some conventional relays include an operation indicating light so that an operator easily checks an operation of the relay. The operation indicating light is turned on or off in accordance with an opening or closing operation of the relay. Generally, in order for an operator to easily visually recognize, from an outside of the relay, whether the operation indicating light is in an ON or OFF state, the relay is desirably configured so that the operator can view light of the operation indicating light from a surface side opposite to a lower surface side of a case on which lower surface the relay is provided, that is, from an upper surface side of the case.
According to, for example, a relay disclosed in Patent Literature 1, a light guide path is provided outside of a case (housing) so as to extend in an up-and-down direction along a side surface of the case. An upper surface of the light guide path is level with an upper surface of the case, and serves as a display surface of the light guide path. Light emitted from a light source (light-emitting means) provided in the case (i) enters the light guide path via a lower end part of the light guide path, (ii) is guided in the light guide path, and (iii) then exits from the display surface that is the upper surface of the light guide path. As such, Emission of light from the light source leads to causing the light to exit from the display surface of the light guide path on an upper surface of the relay.
However, according to the relay disclosed in Patent Literature 1, the light which exits from the display surface is less uniform, and has a narrow directional angle. Therefore, even in a case where light exits from the display surface due to emission of the light from the light source, it is difficult to view the light when the relay is observed from an oblique direction (a direction oblique with respect to a direction perpendicular to the upper surface of the relay). Particularly, in a case where a control panel is provided with multiple relays, an operator should observe the relays one after another from a direction perpendicular to upper surfaces of the relays while sequentially shifting a position of the head of the operator along an arrangement of the relays so as to check whether or not each of the relays is emitting light. This is very troublesome.
Note that the upper surface of the case of the relay of Patent Literature 1 is processed so that a diffuse reflection surface is present around the display surface. This diffuse reflection surface diffuses light which leaks from around the display surface so as to improve visibility of the display surface. However, this diffuse reflection surface is provided outside of an optical path of the light which exits from the display surface, and light less leaks from a side surface of the light guide path. Therefore, the diffuse reflection surface is just a mere surface which can emphasize a state of the display surface viewed from the front of the display surface. This diffuse reflection surface does not allow an operator to clearly check, from the oblique direction, a state where the light source emits light.
Patent Literature 2 discloses a relay that includes a light guide path (a member which guides light and causes the light to exit) having a lower end surface that faces a light source and an upper end surface where a lens is provided. However, this lens is not a lens for diffusing light but a lens for collecting light. Therefore, even according to the relay disclosed in Patent Literature 2, it is remarkably difficult to find, from an oblique direction, that the light source emits light, though it is possible to easily find that from a direction perpendicular to an upper surface of a case.